I have a north facing ground-floor kitchen with the sink under the window, I had a leak under it a couple of months ago which is fixed, but I do see some black mould on the wall behind the cabinet next to the sink. I've put a hydrometer there and it's always above 70%, though I have got it into the 60s by leaving cupboard doors open. Obviously I can't be leaving the doors open all the time, and or running a fan a dehumidifier under there constantly. Wondering if the only real solution would be to take a chunk out the front wall just above the dpc and put a 100mm vent in? I do leave the kitchen windows open all the time, but seems it's not enough.